Elevator closure systems



March 24, 1959 J. K. KRAFT ETAL 2,878,898

ELEVATOR CLOSURE SYSTEMS Filed Dec. 2l. 1953 5 Sheeis-Sheet 1 r 29x H 27 O 1 l f l ATTORNEY March 24, 1959 J. K. KRAFT ET AL 2,878,898

ELEvAToR cLosuRE SYSTEMS Filed Dec. 21, 1953 3 Sheets-Shea?, 2

March 24, 1959 J. K. KRAFT ET AL- 2,878,898

ELEVATOR cLosURE: SYSTEMS 5 Sheets-Sheet 3 Filed DeC. 2l, 1953 lsgb United States Patent O ELEVATOR CLOSURE SYSTEMS Joseph K. Kraft, Verona, and Lennius R. Rissler, Hohokus, NJ., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Penn- Sylvania Application December 21, 1953, Serial No. 399,312

S Claims. (Cl. IS7-S2) This invention relates to closures which are sensitive to the presence of the objects in the closing paths of the closures and it has particular relation to elevator systems having doors provided with object-detecting devices.

A'lthough aspects of the invention are applicable to closures designed for various applications, the invention is particularly suitable for closures or doors employed in elevator systems. Consequently, the invention will be described with particular reference to elevator closures or doors.

In accordance with the invention, a door is provided with a door operator and an objectoetecting device which is positioned adjacent that edge of the door which is the leading edge during a closing operation of the door. The object-detecting device cooperates with the door operator and senses the presence of an object in the closing path of the door in suiiicient time to stop or to stop and reverse the door before an objectionable impact can take place between the door and the object.

The object-detecting device may be associated with hoistway doors or car doors of an elevator system. lf the elevator system has both car and hoistway doors, the object-detecting device conveniently may be associated with the car door and may be positioned in the space normally provided between the car and hoistway doors. When so positioned, the object-detecting device provides substantial protection for both the car and hoistway doors. Preferably, the entire object-detecting device is releasable as a unit from the door with which it is associated.

In accordance with a further aspect of the invention, the object-detecting device is adjusted in position in accordance with the position and movement of the door with which it is associated. When the door is in its fully opened position, the object-detecting device `is in a retracted position with respect to the door. Following initiation of a door closing operation, the object-detecting device is rapidly projected into a leading position with respect to the associated door. This leading position is maintained for at least the major part of the door closing operation. As the door nears the end of its closing movement, the object-detecting device preferably is retracted with respect to the door to a less leading position. The object-detecting device may be maintained in a retracted position during the subsequent door opening operation. Alternatively, the object-detecting device may be in the aforesaid leading position during a major part of the opening movement of the door. ln a preferred embodiment of the invention, the object-detecting device remains sensitive to the position of an object with respect to the doo1 for all positions of adjustment of the object-detecting device with respect to the associated door.

Adjustments of the object-detecting device with respect to the associated door preferably are effected with harmonic motion. Thus, when the object-detecting device is to be adjusted to a new position, it is moved rapidly at lirst and thereafter is moved at a rate which appreaches zero as the object-detecting device nears its new position of adjustment.

lt is, therefore, an object of the invention to provide a closure having an improved object-detecting device.

It is a further object of the invention to provide a door having an object-detecting device which is adjustable to various positions with respect to the associated door.

lt is another object of the invention to provide a door having an Yobject-detecting device which is in retracted position relative to the door when -the door is in open position and which is projected to a leading position with respect to the associated door as a closing operation of the door is initiated.

It is also an object of the invention to provide a door having an object-detecting device which is maintained in a leading position with respect to the associated door during at least a major part of the door closing operation which is retracted to a less leading position as the door completes its closing operation.

It is a still further object to provide a door having an object-detecing device which is adjustable to various positions with respect to the door and which is sensitive to the position of an object relative to the door in such positions of adjustment of the object-detecting device.

It is an additional object of the invention to provide a door having an object-detecting device which is maintained in a leading position relative to the door over at least a substantial part of the closing movement of the door and which is maintained in a retracted position during at least a major part of the opening movement of the door.

Further objects of the invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which:

Figure l is a View in front elevation with parts broken away of an elevator car having a closure system embodying the invention;

Fig. 2 is a view taken along the line II-II of Fig. 1, with parts broken away, wherein the elevator car of Fig. l is shown in association with a portion of its hoistway;

Fig. 3 is a view in front elevation of one of the doors employed in the closure of Fig. 1;

Fig. 4 is a detail view illustrating mechanism employed in an object-detecting device associated with the closure of Fig. l;

Fig. 5 is a sectional view taken along the line V-V of Fig. 4;

Fig. 6 is a detailed view showing a portion of the mechanism employed in the object-detecting device provided for the closure of Fig. l;

Fig. 7 is a view in side elevation illustrated in Fig. 6;

Fig. 8 is a schematic view of an electrical system suitable t'or operating the closure of Fig. l;

Figs. 9, l0 and ll are views in front elevation with parts broken away showing various positions of one of the doors together with the associated object-detecting device employed in the closure of Fig. l;

Fig. l2 is a view in front elevation with parts broken away of a door having a modified object-detecting device associated therewith;

Fig. 13 is a detail view showing mechanism employed in the object-detecting device of Fig. l2; and

Fig. i4 is a View in front elevation with parts broken away of switch operating mechanism suitable for controlling the operation of closures.

Referring to the drawings, Fig. 1 shows an elevator car 1 having a door opening 3 through which passengers enter and leave the elevator car. This door opening may be closed by doors in a conventional manner. For eX- ample, the doors may be single-speed or two-speed doors and they may be side-opening or center-opening doors.

of the mechanism 3 For present purposes, it will sufiiceto describe the invention as applied to doors of the single-speed centeropening type. To this end, two center-opening doors 5 and A5 are illustrated in Fig. l. A number of similar components are employed for the doors 5 and A5. Insofar as is practicable, acomponent for the door A5, which is similar to a component for the door 5, will be identied by the same reference character employed for the component associated with the door 5, to which the prefix A is added.

The door 5 is provided with a door hanger 7, on which door hanger wheels 9 are mounted for rotation. The door hanger wheels for the two doors 5 and A5 are positioned for movement along a horizontally-mounted track 11 in a conventional manner. The track 11 is secured to the elevator car 1.

Movement of the door 5 is effected by a lever 13 which is pivotally mounted on the elevator car 1 by means of a pin 15. The lower end of the lever 13 is pivotally connected to one end of a link 16, the other end of the link being pivotally connected to the door 5. By inspection of Fig. 1, it will be observed that the lever 13 is coupled to the lever A13 by a link 17 which has its ends pivotally attached to the levers 13 and A13, respectively, by pivots 19 and A19. It will be observed that the pivot 19 is positioned above the pin 15, whereas the pivot A19 is located below the pin A15. Consequently, rotation of the lever 13 to open the door 5 moves the link 17 in the proper direction to open the door A5.

The lever preferably is operated by a suitable door operator 21 which may include a reversible electric motor 23 coupled through suitable gearing to a shaft 25. The

shaft 25 carries an arm 27 which is pivotally connected f to one end of a link 29, the remaining end of the link 29 is pivotally connected to the lever 13. Consequently, the motor 23 may be energized in a conventional manner for the purpose of opening and closing the doors.

i `It is conventional practice to provide the hoistway in which the elevator car 1 operates with hoistway doors at each landing served by the elevator car which are similarto the doors 5 and A5 of the elevator car. For example, in Fig. 2, the hoistway 31 in which thev elevator car 1 operates is provided with an opening 33 for each landing served by the elevator car. Each of the openings is closed or exposed by hoistway doors similar to the doors employed for the elevator car. Thus a door 35 is provided which is similar to the door Sof the elevator car. The hoistway door is mounted on hanger wheels 37 which operate along a horizontal track 39 secured to the hoistway wall. It will be assumed that when the elevator car is at a landing, the doors 5 and 35 are connected for simultaneous movement by the door operator. Such operation of car and hoistway doors is conventionalyin the art and is illustrated for example in the Rissler Patent 2,517,713 and Patent 2,502,995.

. During closing movement of the doors, one or more objects may be located in the closing paths of the doors.

lsoeiated with the object-detecting device 41. Consequently, movement of the member 53 substantially in a vertical direction operates to advance and retract the object-detecting device 41 with respect to the door 5. In all positions of adjustment of the object-detecting device, the device remains substantially parallel to the adjacent edge of the door 5.

The tie-member 53 is biased in an upward direction by means of a spring 55 (Fig. 3) which has one end secured to a bracket 57 adjustably mounted on the tie member 53 and one end secured to a pin 59 mounted on the back plate 47. The tie member is moved against the bias of the spring by means of a flexible member 61 which ymay be in the form of a chain or cable. The cable 61 has one` end secured to a pin 63 mounted on the tie member 53. The remaining end of the cable 61 is secured to one end of a bell crank 65 which is pivotally mounted on the door 5. The remaining end of the bell crank 65 is provided with a cam follower roller 67. The cable 61 passes around an idler roller 68 which is mounted on the back plate 47 for rotation about the axis of the roller. The roller may have a peripheral groove for reception of the cable.

When the tie member 53 is lowered, it may be retained in lowered position by means of a suitable latch. Thus in Fig. 3 a latch in the form of a lever 69 is pivotally mounted on the back plate 47. One end of the lever is resiliently connected to the upper end of the bell crank 65 through a spring 71, the upper end of the lever 69 is provided with a lip 73 which in latching position engages a lug 75 which is secured to the tie member 53. The latch lever 69 is biased into latching position by means of a spring 77 which is located between the lip 73 and a bracket 79 which is secured to the back plate 47.

The movement of the tie member 53 with respect to the back plate 47 is limited by suitable stops. For eX- ample, as shown in Figs. 6 and 7, the back plate 47 has secured thereto a bracket 83 through which a threaded screw 85 extends. This screw is secured to the bracket 83 by means of nuts 87 and has threaded stop members 89 and 91 secured to its ends. The tie member 53 has stop brackets 93 and 97 adjustably secured thereto. Thus the bracket 93 has a leg which is threaded for reception of two cap screws 99 which extend through a vertical slot 101 in the tie member, the heads of the screws being too large to pass through the slot. These cap screws may be loosened to permit adjustment of the bracket with respect to vthe tie member. The bracket has a leg 103 extending at right angles to the tie member for the purpose of engaging the stop member 89. In a similar manner, the bracket provides a leg 105 for engagement with the stop member 91. When the tie A member is in its lowest position with respect to the back To prevent undesired impact between each of the doors v and such an object, the door 5 is provided with an objectdetecting device 41. The object-detecting device is located adjacent that edge of the door 5 which is the leading edge during a closing operation of the door. Conveniently, the object-detecting device may be mounted on brackets 43 and 45 which are secured to a back plate 47. Consequently, by releasably mounting the back plate 47 on the door 5, the entire detecting device 41 may be removed as a unit from the door 5.

" As previously pointed out, the object-detecting device plate 47, the leg 103 engages the stop member 89. When the tie member is in its highest position with respect to the back plate, the leg 105 engages the stop member 91.

Each of the object-detecting devices includes an object-detecting element which extends substantially parallel to the edge of the associated door which is the leading edge during door closure. For example, in Fig. l, the object-detecting devices 41 and A41 include objectdetecting elements or nosings 107 and A107, respectively.

The object-detecting device 41 includes translating means responsive to the position of an object relative to the door 5. Various types of translating means have been proposed in the prior art. For example, the translating means may be designed to depend for operation on an electric field extending ahead of the detecting element 107 during door closure. The variation of the electric field by an object in the closing path of the door operates the translating means to initiate a stopping or reversal of the door. In another form, the translating means may be responsive to movement of the detecting element as Y set forth, for example, in the copending Rissler applica tion, Serial No. 287,720, filed May 14, 1952, and assigned to the same assignee.

In a preferred embodiment of the invention, movement of the detecting element 107 by an object in the closing path of the door is lemployed for operating the translating means. The translating means will be discussed now with particular reference to Fig. 3.

Preferably, however, movement of the detecting yelement 107 relative to the bell cranks 49 and 51 is employed for operating the translatingmeans. To this end, links 109 and 111 have their lower ends pivotally connected, respectively, to the upper ends of the bell cranks 49 and 51, whereas the upper elements of the links are pivotally connected to the detecting element 107. The links 109 and 111 are given a limited range of movement about their pivotal connections to the detaching element. As shown in Fig. 3, the force of gravity operating on the detecting element 107 holds the links 109 and 111 at one extreme of their limited ranges of movement relative to the detecting element. If the detecting element 107 is deected to the left relative to the door 5 by engagement with an object in the closing path of the door, the links 109 and 111 are moved in counterclockwise directions about their pivotal connections to the detecting element. This movement of the links is employed for operating suitable translating means such as one or more electric switches. Thus an electric switch 113 is positioned to be operated by a switch operating member 109a projecting from the link 109. The switch 113 is suitably secured to the detaching element 107.

A suitable construction for the detecting element is illustrated in Fig. 5. As shown in Fig. 5, the detecting element 107 may take the form of a nosing having a channel conguration. Preferably the web of the channel is rounded, as illustrated in Fig 5. It will be noted that various parts of the detecting device are located within the channel formed by the nosing. For example, a portion of the bracket 45 extends into the nosing and has a forked conliguration. Substantial portions of the bell crank 51 also are positioned within the nosing. It will be noted that the bell crank 51 is located within the fork of the bracket 45 and is pivotally connected to the bracket by means of a suitable pin 117.

The bracket 45 is spaced from the back plate 47 by means of a spacer 119 and is secured to the back plate by means of bolts 120 which extends through the back plate, the spacer 119 and a portion of the bracket.

As shown in Fig 5, the tie member 53 may be in the form of an angle having a leg 53a extending parallel to, but spaced from, the back plate 47. A second leg 53b of the angle extends towards the back plate 47. Consequently, the angle 53 and the back plate 47 dene a space within which portions of the object-detecting means may be located. For example, such portions may include the spring 55 (Fig. 3) and the latch 69.

The nosing 107 may be constructed of any suitable material such as a plastic. A light-weight plastic such as a phenolic resin is very satisfactory. Alternatively, the nosing may be constructed of a light-weight metal, such as aluminum. In a preferred embodiment of the invention, the nosing 107 comprises a layer 107R of flexible, resilient material, such as rubber, which yis cemented or secured to a support member 107a of rigid, light-weight material, such as aluminum. The support member 107a is in the form of a channel which has a web 107b. The rubber layer forming the nosing 107 and the support member 107a form a pair of nested channels having their edges cemented together and having their webs 107b and 107e respectively spaced from each other as clearly shown in Fig. 5. If an Objectis in the closing path of the door, the resilient web 107e is the first part of the door assembly to engage the object and thus cushions the impact.

It will be clear from Figs. 2 to 5 that when the elevator car is located at a landing, the object-detecting device 41 is located substantially between the elevator car door 5 and the associated hoistway door 35. Consequently, the

6 object-detecting device provides adequate protection forboth `oi the doors with respect to objects which are substantially in the closing pathsl of the doors. Furthermore, if the doors are closed and the object-detecting device is in retracted position, the object-detecting device is substantially concealed and protected by the doors.

The linkage associated with the bell crank 51 s illustrated on a large scale in Fig. 4. It will be noted that the link 111 is pivotally connected to the upper end of the bell crank 51 by means of a pin 121. The link 111 also is pivotally connected to the nosing 107 and the support member 107a by a pin or screw 123. The link 111 has a projection 111a which is associated with stops for limiting rotation of the link 111 about the axis established by the screw 123. It will be noted that the screw 123 is mounted on a bracket 125 which is secured to a second bracket 127 by means of screws 129. The second bracket 127 is suitably secured to the nosing 107. A stop screw 131 is in threaded engagement with the bracket and is secured in any position of adjustment by means of a lock nut 133. By inspection of Fig. 4, it will be observed that the stop screw 131 may be adjusted as desired to limit rotation of the link 111 about the screw 123 in a counterclockwise direction.

A second stop screw 13S is secured to the projection 111a by means of a nut 137. This screw projects through a leg of the bracket 127 and has a stop nut 139 positioned thereon. This stop nut is locked in any position of adjustment by means of suitable lock nuts 141. By inspection of Fig. 4, it will be observed that the stop nut 139 limits rotation of the link 111 in a clockwise direction about the screw 123.

As viewed in Fig. 4, the screw 123 is located to the right of the pin 121. Consequently, the weight of the nosing 107 maintains the stop nut 139 in engagement with the associated leg of the bracket 127. If the nosing 107 engages an object during a closing movement of the door, the resultant movement of the nosing relative to the bell crank 51 rotates the link 111 in a counterclockwise direction until the projection 111a engages the stop screw 131. This movement may be of the order of SAG of an inch and may be employed for operating suitable translating means, such as a switch. If the nosing is in its advanced or leading position when it engages the object, continued movement of the door with respect to the object results in rotation of the bell crank 51 in a counterclockwise direction relative to its supporting bracket. This movement of the bell crank 51 preferably is sutlcient to permit the elevator car door to be brought to a stop before the bell crank reaches its limit of rotation.

It will be understood that the bell crank 49 (Fig. 3), the link 109 and the projection 10911 are constructed and operate in a manner .similar to those discussed for the bell crank 51, the link 111 and the projection 111a. It will be recalled that motion of the projection 109er is employed for operating a switch 113. This switch may be normally open and may be operated to its closed condition by rotation of the projection 109a in a counterclockwise direction about its pivot. Alternatively, the switch 113 may be normally in a closed condition and maybe opened by the aforesaid motion of the projection 10911. It will be recalled that motion of the nosing of the order of of an inch suiiices for operation of the switch.

When the nosing initially engages an object in the closing path of the door, the nosing is brought to a stop. Since the nosing is extremely light in weight and sinceit operates comparatively few parts during the initial movement thereof, an extremely sensitive object-detecting device is provided.

In order to illustrate `a suitable operation of the electric switch 113, a simple schematic diagram is shown in Fig. 8. In this diagram, the armature 23A and the field winding 23F of the door operating motor 23 (Fig. l) are illustrated. The switches 113 and A113 are connected in series with the energizing coil of a door-safety relay-'DR 'acrossthe direct-current buses L+ and L. -Consequently, asilong as the switches 113 and A113 remain closed, the relay DR remains energized and picked up to close its make contacts DRI, DRZ and DRS and open its break contacts DR4. Under normal conditions, the motor is energized to open or close the doors by operation of a switch SW. Although this may be a manually operated switch, in a preferred embodiment of the invention, this switch represents the contacts of a relay or relays employed in any conventional door-operating system to initiate an opening or closing operation of the doors. Assuming that the doors initially are in their open condition, movement of the operating member of the switch SW up closes contacts SW1 to complete with the limit switch 151 and the contacts DR3 a circuit connecting the door-closing relay CL across the buses L1 and L2 for energization. The relay CL closes its contacts CL1 and CL2 to complete the following energizing circuit:

L+, DRz, CL2, zar, CL1, D111, 23A, L-

This circuit energizes the motor for operation in the door-closing direction. As the doors near their fullyclosed condition, they open the limit switch 151 to interrupt the energizing circuit for the door-closing relay CL. This relay thereupon drops out to terminate the energization of the door-closing motor.

If the doors are to be opened, the operating member of the switch SW is operated down to close its contacts SW2. These contacts, together with the limit switch 153, complete an energizing circuit for the opening contacts OP. Consequently, the relay closes its contacts OPI. and OPZ to complete the following circuit:

L+, OPI, 23F, OPZ, 23A, L-

The motor now is energized in proper direction to open the doors. As the doors near their fully-open position, the limit switch 153 opens to deenergize the door open ing relay OP. This relay opens its make contacts OPI and OP2 to deenergize the field winding 23F and the armature 23A.

Let it be assumed that during a door-closing operation, an object in the closing path of the door 5 (Fig. 3) engages the nosing 107 to operate the switch 113. The resulting opening of the switch 113 deenergizes the doorsafety relay DR (Fig. 8) and this relay thereupon opens its make contacts DRl and DR2 to deenergize the field winding 23F and the motor armature 23A. Consequently, the doors are brought to a stop. Contacts DRS also open to interrupt the energizing circuit for the door closing relay CL. If desired, the deenergization of the door safety relay DR also may be accompanied by reopening of the doors. To this end, break contacts DR4 are provided which are closed when the door-safety relay DR is deenergized to complete with the limit switch 153 an energizing circuit for the door-opening relay OP.

In practice, a more complicated door operating circuit would be employed with suitable checking provisions for the door. A typical system for energizing a door-operating motor will be found in the McCormick Patent 2,235,380.

The advancing and retracting operation of the door safety device now will be considered. In Fig. 9, the door 5 is shown moving in the door-closing direction represented by the arrow 155. The nosing 107 is in its fully advanced position. In this advanced position, the tie member 53 occupies its highest position and is maintained in this position by the spring 55 (Fig. 3). It will be noted that the lug 75 (Fig. 9) is positioned above the latch 69 with which it is associated.

lf an object is encountered by the nosing 107 during the closing operation of the door, the nosing is brought to a stop while the door continues to advance. During such advance, the link 111 rotates relative to the bell crank 51 whichremains `stationary relative to the doorV 5.

When the door 5 has moved a distance of approximately @is of an inch relative to the nosing 107, the switch 113 (Fig. 3) operates to initiate a stopping operation of the door 5 in the manner set forth above. However, the kinetic energy ofthe door 5 is such that the door continues its motion relative to the nosing 107. As a result of this continued motion, the bell crank 51 is rotated by the nosing 107 to lower the tie member 53. This motion of the bell crank continues until the door is brought to a stop. In a conventional closure system, a distance on the order of 2 to 3 inches usually suices for the purpose of bringing the door to a stop. Consequently, the parameters of the object-detecting device are such that the nosing 107 can move from its fully-advanced position relative to the door 5 for a distance of the order of say 2 inches. Consequently, the door 5 is brought to a stop before it can apply its kinetic energy to the object which initiated the stopping operation of the door. Under the assumed conditions, the door is reversed and reopens. The movement of the door relative to the nosing may be suicient to bring the lug 75 beneath the latching lip of the latch 69. If this occurs, the latch retains the nosing in retracted position throughout the opening operation of the door.

Let it be assumed next that door is closing in the direction of the arrow of Fig. 9 and that no object is present in the closing path of the door. Under such circumstances, the door continues its closing motion and the cam follower 67 eventually engages the cam C2. The bell crank 65 now is rotated by the cam follower 67 and the cam C2 into the position illustrated in Fig. 10. During such rotation, the cable 61 is operated by the bell crank 65 to lower the tie member 53. In lowering, the tie member 53 rotates the bell crank 51 relative to the door for the purpose of retracting the nosing 107. This retracting operation preferably starts immediately before the nosings of the two doors 5 and A5 (Fig. l) touch each other.

At the same time, the lug 75 is lowered by the tie member 53 to which it .is secured until it is positioned below the latching lip of the latch 69. The spring 77 projects the latch 69 into latching position.

When the door 5 is to be reopened, the initial motion in the opening direction represented by the arrow 157 causes the cam follower 67 to ride down the cam C2. The resulting rotation of the bell crank 65 in a counterclockwise direction relative to the door 5 releases the cable 61 and the tie member 53 starts to ascend. However, the latch 69 now engages the lug 75 to retain the tie member in its lowered position. Therefore, the latch 69 maintains the nosing 107 retracted during the entire opening operation of the door.

In a preferred embodiment of the invention the nosing 107 is allowed to project from the associated door for a distance of the order of one-half inch when the nosing is in retracted position.

As the door 5 nears its fully open position, the cam follower 67 engages the cam C1 (Fig. ll) to rotate the bell crank 65 in a counterclockwise direction relative to the door 5. This rotation increases the spring force exerted on the latch 69, but this spring force is so pro.- portioned that it is insufficient to overcome the opening friction of the latch 69. However, in the final stage of its rotation, the bell crank 65 operates through the flexible member 61 to lower the tie member 53 slightly. Such lowering of the tie member releases the latch suiciently to permit the force exerted by the spring 71 to overcome the latching force exerted by the spring 77 and the latch thereupon moves to the position illustrated in Fig. ll.

However, the bell crank 65 maintains the tie memberV in its lowered position as long as the door remains open. lIt should be noted that the transfer from the latching condition to the condition wherein the tie member is transferred to control by the flexible member 61 is effected smoothly. f

When the door is to be reclosed, the initial movement of the door causes the cam follower 67 to ride down the cam C1. The resultant rotation of the bell crank 65 releases the flexible member 61 and permits the tie member 53 to move for the purpose of advancing the nosing 107. The force stored in the spring 71 is sufficient to maintain the latch 69 released until the projection 75 rises above its latching position.

The contour of the cam C1 is selected to assure a smooth advance of the nosing 107 without rebound. Preferably, the nosing is projected rapidly following initiation of the door opening operation and the advance of the nosing relative to the door 5 is slowed as the nosing nears its fully advanced position. The parameters may be so selected that the nosing is fully advanced within approximately two inches of door motion from the fullyopened position.

It should be noted that the nosing 107 is fully effective to operate the switch 113 (Fig. 3) in all positions to which the nosing may be advanced or retracted.

A somewhat different mounting of the nosing is illustrated in Fig. 12. As shown in Fig. 12, a nosing 161 which corresponds to the nosing 107 of Fig. 1 is mounted adjacent an edge of a door 163 which corresponds to the door 5 of Fig. 1. The nosing 161 is mounted adjacent that edge of the door which is the leading edge during a closing movement of the door and is mounted by means of parallel links 165 and 167. Each of these links is pivoted at one end to the door and at the other end to the nosing 161. By inspection of Fig. l2, it will be observed that the weight of the nosing 161 urges the nosing toward the right relative to the door, as viewed in Fig. 12. In the extended position of the nosing, a hook 169 secured to the nosing engages the operating member of an electric switch 171 which is secured to the door 163 and maintains the switch in closed condition. The switch is biased towards open condition. Consequently, motion of the nosing 161 toward the door 163 results in opening `of switch 171. The switch 171 corresponds to the switch 113 of Fig. 3.

When the door 163 is closed, the nosing 161 engages the nosing of the associated door if center-opening doors are employed, or it engages the jamb if a single door is employed, to force the nosing into retracted position relative to the door 163. During such retraction of the nosing, it may be desirable to shunt the switch 171 and a limit switch (to be discussed below) may be provided for such purpose.

The nosing 161 may be held in retracted position by means of an electromagnet 173, which is secured to the door 163. A magnetic armature 175 is secured to the nosing for the purpose of substantially completing a magnetic circuit for the electromagnet when the nosing is in retracted position. The electromagnet assembly is shown in somewhat more detail in Fig. 13. The electromagnet may be energized by a limit switch as the door completes a closing operation and it may be maintained energized as long as desired for the purpose of maintaining the nosing retracted. If the nosing is to be advanced following initiation of a door closing operation, the electromagnet is deenergized at thistime to permit the nosing to advance.

The advance of the nosing may be assisted by a spring 179 which is interposed between a bracket 177 secured to the door 163 and the nosing. if the nosing is to advance relative to the door for a distance of the order of 3 inches, the spring may be made effective to assist in advancing the nosing during the first l and 1/2 inches of the advancing movement. Since the spring 179 is not effective while the nosing is in ullyadvanced position, maximum sensitivity of the nosing is assured.

In order to prevent rebound of the nosing as it is advanced, suitable cam means is provided for controlling the rate at which the nosing may be advanced relative to the door. To this end, the link 165 has a projection provided with a cam follower 181. This cam follower when the nosing is in retracted position is received within a cam 183, which is mounted on the door 163. During an advancing operation of the nosing 161, the cam follower 181 rides along the earn 183 to permit a rapid initial advance of the nosing with a smooth slowdown of the nosing as it reaches its fully advanced position.

It may be desirable to shunt the switch 171 during the initial advance of the nosing. To this end, a limit switch may be provided to provide such shunting operation.

As above indicated, limit switches may be provided to assist in the operation of the door assembly. A suitable limit switch assembly is illustrated in Fig. 14. Referring to Fig. 14, a shaft 185 is provided which is rotated through suitable gearing by the motor 23 of the door operator (Fig. 1). The shaft has secured thereto cams 187 and 189 for operating suitable limit switches. The shaft 185 rotates relative to a housing 191 on which the switches may be mounted. Two switches 193 and 195 are illustrated having cam followers 193a and 195e, respectively, for operation by the cam 189. These switches are secured to brackets 193b and 195b on the housing 191 by screws 197 which extend through elongated slots in the brackets which mount the switches. Consequently, by releasing the screws 197, the switches may be adjusted relative to thel housing to adjust the point at which the cam 189 engages the switch for the purpose of operating the switch.

Two additional switches include leaf springs 199 and 201 which are secured at one end to the housing 191. Each of the springs has a contact button 199a and 201a which is biased respectively into engagement with a fixed contact button 199b and 201b, respectively. Each of the springs has a cam follower 199e and 201C, respectively, which is positioned for engagement by the cam 187. By inspection of Fig. 14, it will be noted that rotation of the cam 187 results in opening and closing of the switches represented by the contacts 199a and 19917 and by the contacts 201a and 201b at predetermined points on the rotation of the cam. By proper contouring and location of the cam, the switches may be designed to operate as desired.

If desired, shock-absorbing devices may be employed to minimize shock and noise resulting from manual retraction and release of the nosing. For example, in Fig. 6 an air dashpot DP is illustrated in broken lines for pivotal connection to the bracket 97 and to the pin 59. This dashpot cushions movement of the tie member 53 relative to the back plate 47 and is designed to retard gently the motion of the nosing as it approaches its fully-advanced position. If retardation in the retracting direction is not desired the dashpot may be of the oneway type which does not retard motion of the nosing in the retracting direction.

Although the invention has been described with respect to certain specific embodiments thereof, numerous modifications falling within the spirit and scope of the invention are possible.

We claim as our invention:

1. In a closure system, a structure having an opening, and a door unit comprising a door for said opening, means mounting the door for rectilinear movement in the plane of the door relative to the structure to close and expose the opening, and object-detecting means for said door, said object-detecting means comprising a detector element, means mounting the detector element adjacent an edge of said door for movement with the door and for adjustment relative to the door in a direction having a component parallel to the direction of movement of the door, and latching means effective as a closing movement of the door is completed for decreasing the lead of said detector element relative to the door to place the detector element in a retracted position, said latching means retaining the detector elementin said retracted position during the entire opening movement of the door, and latch releasing means eective as a closing movement of the door is initiated for releasing said latching means to permit advance of said detector element relative to the door to position the detector element in a leading position relative to the door during a substantial portion of the reclosing movement of the door.

2. In a closure system, a structure having an opening, and a door unit comprising a door for said opening, means mounting the door for rectilinear movement in the plane of the door relative to the structure to close and expose the opening, and object-detecting means for said door, said object-detecting means comprising a detector element, means mounting the detector element adjacent an edge of said door for movement with the door and for adjustment relative to the door in a direction having a component parallel to the direction of movement of the door, and latching means elective as a closing movement of the door is completed for decreasing the lead of said detector element relative to the door to place the detector element in a retracted position and latching the detector element in said retracted position throughout an opening movement of the door, and latch-releasing means effective as a closing movement of the door is initiated for releasing said latching means to permit advance of said detector element relative to the door to position the detector element in a leading position relative to the door during a substantial portion of the reclosing movement of the door, said latch-releasing means comprising mechanical mechanism responsive to the movement of the door unit relative to the structure for placing said latching means in ineffective condition. v

3. In a closure system, a door, a detector element positioned adjacent one edge of the door, a pair of similar bell cranks positioned for rotation about parallel axes spaced along said edge of the door, a tie element pivotally connected to corresponding rst ends of the ibell cranks, means mounting the tie element for movement relative to the door to rotate said bell cranks, a pair of parallel links associated respectively with the second ends of the bell cranks, each of said links having a irst terminus pivotally connected to the second end of the associated bell crank and a second terminus pivotally connectedto the detector element, means limiting rotation of each of the links about one of its pivots, and switch means responsive to rotation of one of said links about one of its pivots, whereby said tie element may be operated to change the advance of the detector element relative to the door without affecting operation of the switch in response to displacement of the detector element relative to the bell cranks.

4. In a closure system, a structure having an opening, a door mounted for movement to close and expose said opening, a detector element positioned adjacent one edge of the door, a pair of similar bell cranks positioned for rotation about parallel axes spaced along said edge of the door, a tie element pivotally connected to corresponding rst ends of the bell cranks, means mounting the tie element for movement relative to the door to rotate said bell cranks, a pair of parallel links associated respectively with the second ends of the bell cranks, each of said links having a iirst terminus pivotally connected to the second end of the associated bell crank and a second terminus pivotally connected to the detector element, means limiting rotation of each of the links about one of its pivots, and switch means responsive to rotation of one of said links about one of its pivots, whereby said tie element may be operated to change the advance of the detector element relative to the door without alecting operation of the switch in response to displacement of the detector element relative to the bell cranks, and control means effective for operating said tie element to advance the detector element relative to the door lbefore said .door makes a substantial closing 12 movement and for operating the tie element to retard the detector element relative to the door after said door has completed a substantial part of the closing movement.

5. In a closure system, a structure having an opening, a door mounted for movement to close and expose said opening, a detector element positioned adjacent one edge of the door, a pair of similar bell cranks positioned for rotation about parallel axes spaced along said edge of the door, a tie element pivotally connected to corresponding lirst ends of the bell cranks, means mounting the tie element for movement relative to the door to rotate said bell cranks, a pair of parallel links associated respectively with the second ends of the bell cranks, each of said links having a iirst terminus pivotally connected to the second end of the associated bell crank and a second terminus pivotally connected to the detector element, means limiting rotation of each of the links about one of its pivots, and switch means responsive to rotation of one of said links about one of its pivots, whereby said tie element may be operated to change the advance of the detector element relative to the door without aiecting operation of the switch in response to displacement of the detector element relative to the bell cranks, and control means effective for operating said tie element to advance the detector element relative to the door before said door makes a substantial closing movement and for operating the tie element to retard the detector element relative to the door after said door has completed a substantial part of the closing movement, and latching means effective for retaining the tie element in the last-named operated condition during an opening operation of the door.

6. In a closure system, a structure having an opening, a door mounted for movement to close and expose said opening, a detector element positioned adjacent one edge of the door, a pair of similar bell cranks positioned for rotation about parallel axes spaced along said edge of the door, a tie element pivotally connected to corresponding first ends of the bell cranks, means mounting the tie element for movement relative to the door to rotate said bell cranks, a pair of parallel links associated respectively with the second ends of the bell cranks, each of said links having a rst terminus pivotally connected to the second end of the associated bell crank and a second terminus pivotally connected to the detector element, means limiting rotation of each of the links about one of its pivots, and switch means responsive to rotation of one of said links about one of its pivots, whereby said tie element may be operated to change the advance of the detector element relative to the door without aiecting operation of the switch in response to displacement of the detector element relative to the bell cranks, and control means effective for operating said tie element to advance the detector element relative to the door before said door makes a substantial closing movement and for operating the tie element to retard the detector element relative to the door after said door has completed a substantial part ofthe closing movement, and latching means effective for retaining the tie element in the last-named operated condition during an opening operation of the door, biasing means for applying a partial releasing force to said latching means prior to a door closing operation, said control means prior to a door closing operation operating to relieve the latching means suiciently to permit said partial releasing force to release the latching means.

7. In a closure system, a structure having an opening, a door, means mounting the door for movement relative to the structure to close and expose the opening, and object-detecting means responsive to the presence of an object substantially in the path of the door, said objectdetecting means comprising a detector element positioned and biased relative to the door to lead said door during a substantial closing movement of the door, lever means mounting the detector element on the door for movement towards the door in response to engagement of an object by the detector element during a closing movement of the door, said lever means including a rst lever pivotally secured to the detector element for pivotal movement about a iirst axis transverse to the plane of the door, a second lever pivotally associated with the first lever for rotation relative to the first lever a'bout a second axis parallel to and spaced from the first axis, deflection of said detector element relative to the door by an object located in the closing path of the door acting to rotate said iirst lever about the second axis, an electric switch operable between current blocking and transmitting conditions, said electric switch being mounted for operation by the rst lever in response to said last-named rotation of the iirst lever, said first lever and said switch being mounted for movement as a unit in response to movement of the second lever, whereby such movement does not operate the switch, said second lever being operable for applying to the detector element through the rst lever a force acting against said bias to retract the detector element, said lever means including a lever unit connecting the door to the detector element at a point spaced from said axes in the direction of the edge of the door which is the leading edge during a closing movement of the door for maintaining all positions of the detector element relative to the door parallel to each other.

8. In a closure system, a structure having an opening, a door, means mounting the door for movement relative to the structure to close and expose the opening, and object-detecting means responsive to the presence of an object substantially in the path of the door, said objectdetecting means comprising a detector element positioned and biased relative to the door to lead said door during a substantial closing movement of the door, lever means mounting the detector element on the door for movement towards the door in response to engagement of an object by the detector element during a closing movement of the door, said lever means including a pair of parallel spaced first levers each pivotally connected to the detector element for rotation about a separate axis relative to the detector element, the axes being spaced in the direction of the edge of the door which is the leading edge during a closing movement of the door and being transverse to the plane of the door, said first levers mounting the detector element for movement relative to the door in a plane transverse to said axes, an electric switch operable between a current conducting condition and a current blocking condition, said switch being responsive to movement of one of the first levers about the associated one of said axes for operation from one to another of said conditions, a second lever mounted on the door for rotation about an axis transverse to the plane of the door for actuating the rst levers, the switch and the detector element t0 second positions wherein the lead of the detector element relative to the door is decreased, the movements of the switch and the first levers by the second lever being synchronized to prevent switch operation as a result of said rotation of the second lever, and means effective as the door nears an end of its movement for effecting said rotation of the second lever.

References Cited in the tile of this patent UNITED STATES PATENTS 1,890,809 Forman Dec. 13, 1932 1,911,792 Boedtcher May 30, 1933 2,610,268 Hamilton Sept. 9, 1952 2,687,172 Norman Aug. 24, 1954 2,687,455 Norman Aug. 24, 1954 FOREIGN PATENTS 384,551 Great Britain Dec. 8, 1932 

